//BASE64加解密
// private property  
const _keyStr = "abcdefghijklmnopqrstuvwxyz0123456789+/=ABCDEFGHIJKLMNOPQRSTUVWXYZ";  

// public method for encoding  
const encode = function (input) {  
	var output = "";  
	var chr1, chr2, chr3, enc1, enc2, enc3, enc4;  
	var i = 0;  
	input = _utf8_encode(input);  
	while (i < input.length) {  
		chr1 = input.charCodeAt(i++);  
		chr2 = input.charCodeAt(i++);  
		chr3 = input.charCodeAt(i++);  
		enc1 = chr1 >> 2;  
		enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);  
		enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);  
		enc4 = chr3 & 63;  
		if (isNaN(chr2)) {  
			enc3 = enc4 = 64;  
		} else if (isNaN(chr3)) {  
			enc4 = 64;  
		}  
		output = output +  
		_keyStr.charAt(enc1) + _keyStr.charAt(enc2) +  
		_keyStr.charAt(enc3) + _keyStr.charAt(enc4);  
	}  
	return output;  
}  

// public method for decoding  
const decode = function (input) {  
	var output = "";  
	var chr1, chr2, chr3;  
	var enc1, enc2, enc3, enc4;  
	var i = 0;  
	input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");  
	while (i < input.length) {  
		enc1 = _keyStr.indexOf(input.charAt(i++));  
		enc2 = _keyStr.indexOf(input.charAt(i++));  
		enc3 = _keyStr.indexOf(input.charAt(i++));  
		enc4 = _keyStr.indexOf(input.charAt(i++));  
		chr1 = (enc1 << 2) | (enc2 >> 4);  
		chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);  
		chr3 = ((enc3 & 3) << 6) | enc4;  
		output = output + String.fromCharCode(chr1);  
		if (enc3 != 64) {  
			output = output + String.fromCharCode(chr2);  
		}  
		if (enc4 != 64) {  
			output = output + String.fromCharCode(chr3);  
		}  
	}  
	output = _utf8_decode(output);  
	return output;  
}  

// private method for UTF-8 encoding  
const _utf8_encode = function (string) {  
	string = string.replace(/\r\n/g,"\n");  
	var utftext = "";  
	for (var n = 0; n < string.length; n++) {  
		var c = string.charCodeAt(n);  
		if (c < 128) {  
			utftext += String.fromCharCode(c);  
		} else if((c > 127) && (c < 2048)) {  
			utftext += String.fromCharCode((c >> 6) | 192);  
			utftext += String.fromCharCode((c & 63) | 128);  
		} else {  
			utftext += String.fromCharCode((c >> 12) | 224);  
			utftext += String.fromCharCode(((c >> 6) & 63) | 128);  
			utftext += String.fromCharCode((c & 63) | 128);  
		}  

	}  
	return utftext;  
}  

// private method for UTF-8 decoding  
const _utf8_decode = function (utftext) {  
	var string = "";  
	var i = 0;  
	var c = 0, c1 = 0, c2 = 0;  
	while ( i < utftext.length ) {  
		c = utftext.charCodeAt(i);  
		if (c < 128) {  
			string += String.fromCharCode(c);  
			i++;  
		} else if((c > 191) && (c < 224)) {  
			c2 = utftext.charCodeAt(i+1);  
			string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));  
			i += 2;  
		} else {  
			c2 = utftext.charCodeAt(i+1);  
			c3 = utftext.charCodeAt(i+2);  
			string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));  
			i += 3;  
		}  
	}  
	return string;  
}  



export default {
	encode,
	decode
}